Warken noble



Oct. '11, 1932. w. NOBLE 1,881,884

THERMOSTATIC MOTOR Filed March 26, 1930 Igj Z2 2/ lnunmumnmum: J4 J2 Z1 l Cit-150mm Patented Oct. 11, 1932 UNITED STATES PATENT OFFICE WARREN NOBLE, OF DETROIT, MICHIGAN, ASSIGNOR TO ELEGTROMASTER, INO., OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN THERMOSITATIC MOTOR Application filed March 26, 1930. Serial No. 439,251.

This invention relates to switches for electrical circuits and more particularly to thermostatically controlled switch mecharnsm. An object of the invention is to provide a novel switch mechanism which will operate to alternately open and close circuits through alternate lines carrying electric current, and also to utilize the movement of the mechanism as a motor which may be employed as a source of power for accomplishing work exteriorly of the electric circuits.

A further object of the invention is to provide a common lead line for two electrical circuits having a triterminal switch for controlling the particular circuit through which current may flow at any particular instance and to automatically throw this switch by thermostatic means from one circuit closing position to another, utilizing the movement of the switch as a motor.

In accordance with the general features of the invention, there is provided a mercury switch comprising a hermetically sealed bent tube embodying a globule of mercury, there being terminals arranged so that the mercury is free to complete an electrical connection between two of the terminals at any one time, the bent tube and the mercury being pivotally supported so that a tilting thereof will break contact between one of the terminals and establish contact between the other two terminals through the mercury. Thus, if a center terminal of the switch be constantly connected with a source of electric power and a current flows through this terminal, through the mercury globule and out another terminal and a tilting of the switch is instigated the globule will roll or flow downwardly by gravity so that contact with either terminal is broken and contact established with the third terminal, thereby completing a circuit through the center terminal, the globule and the third terminal. In this manner, current flow is controlled through the two circuits. It will be understood that the invention is not limited to this particular type of switch, however, mention of it is specifically madefor the purpose of bringing out the desired operation which will fully 50 illustrate the objects sought.

Another feature of the invention relates to the provision of feasible means by which the automatic tilting of the aforesaid mercury switch is accomplished, this means to comprise a thermostat which may be made of a bi-metallic strip having a resistance coil included in the circuit wound therearound. By utilizing two such thermostats, one in each circuit, I thus provide a positive means for actuating or tilting the switch to alternate positions so that it is then quite feasible to employ a double pawl and ratchet mechanism to translate the tilting or oscillating motion into a more or less continuous rotary motion, the continuity of the motion being dependent only upon the relative size of resistance coil to bi-metallic mass by which the cooling and retraction of the thermostat is controlled.

Other objects and advantages of the invention will more fully appear from the following detailed description taken in connection with the accompanying drawing, which illustrates several embodiments thereof, and in which:

Figure 1 is a diagrammatic view of a themostatically controlled mercury switch hook-up embodying the features of this invention; and

Figure 2 is a diagrammatic view of a modified form of thermostatically controlled switch mechanism embodying the features of this invention.

As shown on the drawing:

The reference characters 10 and 11 designate the two lead lines for supplying electrical current to the thermostatically controlled switch mechanism. One of these lines, such as line 10, is common to both circuits or the switch mechanism and is connected to the middle terminal 13 of a mercury switch comprising a bent tube 12 having disposed therein a globule of mercury 14.

The other line, 11, has connected to it an electrical switch 15 for controlling the flow of current to the mechanism of my invention. Connected to the line 11 are two lines 16 and 17, there being one for each of the two circuits involving this device. The line 16 is connected through a resistance 18 surrounding a bi-metallic strip 19 to the uppermost terminal 20 of the mercury switch. The other line 17 is connected through a resistance 21 surrounding a bi-metallic thermostatic ele ment 22 to the third terminal of the mercury switch. The terminals 29 and 23 are adapted to be alternately connected to the terminal 13 by the mercury 14 as will be come more evident with the progress of the present description.

The two bi-metallic elements 19 and 22 may be made of any suitable thermostatic metal and are arranged so as to fiex in a direction toward each other. One end of each of these elements is attached to a supporting bracket 24 which may be connected to any suitable support. Also, the tube 12 is pivotally connected at 25 to the same support, which is not shown so as to render clear the illustra tion of my invention.

The tube 12 has pivotally connected to each of its two legs apawl for cooperating with the ratchet 28. These pawls are designated by the reference characters 26 and 27, the latter being slightly longer than the former and arranged to engage the under side of the ratchet wheel, whereas the other pawl engages the upper side of said wheel.

The operation of this thermostatically controlled switch mechanism is briefly as follows:

Upon the closing of switch 15, it will be evident that current will flow through the coil 21 around the thermostat 22 and from this coil to the terminal 23 which is connected to the terminal 13 by the mercury 14. As soon as the resistance 21 heats the thermostat 22 to a predetermined degree, this thermostat will flex in a direction toward the element 19 until it assumes the dotted line position shown in Figure 1. During this movement of the element 22, it will strike the upper end of the bent mercury tube 12, thus moving the tube about its pivot, whereby the mercury is enabled to establish contact between the contral terminal 13 and the terminal 20, thus breaking the electrical connection between the terminal 23 and the central terminal 13.

It will, of course, be evident that this movement of the tube 12 results in a down-j ward movement of the pawl 26, whereby it rotates the ratchet wheel 28 to a predetermined extent. Also, while the coil 21 is heating the element 22, the coil 18 around element 19 is gradually cooling so that the thermostatic element 19 is allowed to return to its original position shown by the dotted lines in Figure 1.

Of course, as soon as the contact is established between terminals 13 and 20 in the mercury switch, the current will be shifted from the line 17 due to the breaking of the contact between terminals 23 and 13 to the resistance wire or coil 18, thus heating the thermostatic element 19 and causing it to flex to the full line position shown in Figure 1. This flexing of the element 19 results in the pivoting of the tube 12 back to the full line position shown in Figure 1, which movement results in the pawl 27 being moved downwardly to actuate the ratchet 29 to a predetermined extent. Also this movement of the tube 12 breaks the electrical contact between the center terminal 13 and the terminal 20 and establishes contact between the terminals 13 and 23.

Obviously, since contact between terminals 13 and 20 is broken, the current will be shifted from line 16 to line 17, thus heating the coil 21 and repeating the previously described operation.

Incidentally, it is to be noted that the pawls 26 and 27 are held in cooperation with the teeth of the ratchet 28 by means of springs 29 and 30 connecting the pawls to the tube 12. Moreover, the ratchet wheel 28 is secured to a shaft 31 so that this shaft is rotated by the ratchet wheel. This arrangement enables the ratchet and its shaft 31 to be used as a motor which may be employed as a source of power for accomplishing any work desired exterior of the electric circuit.

In Figure 2 I have illustrated a modification of the invention in which a slidablc switch construction is used in place of the mercury tube 12 as shown in Figure 1. In this hookup, the intake power leads are des ignated by the reference characters and 41. The line 41 is common to both circuits involved in this device, and its free end is connected to the movable switch element 42 of a switch construction 43, which will be described more in detail hereinafter. The other power lead 41 includes a switch 44 which controls the flow of current through the device of my invention. Also connected to the line 41 are two separate lines 45 and 46, there being one for each of the two circuits involved. One of these lines 45 is connected to a coil 47 surrounding the bimetallic thermostatic element 48 to a switch contact element 49 of the switch construction 43. The other line 46 is connected through a resistance wire 50 disposed about the bimetallic thermostatic element 51 to the third terminal or contact 52 of the switch construction 43. The two contacts 49 and 52 are separated by an intermediate insulating member 53. The arrangement of the switch 43 is such that the contact 42 is movable to alternately engage either of the two contacts 49 and 52. The bimetallic elements 48 and 51 are so arranged as to flex in a direction toward each other and are carried by the bracket 55 suitably carried by a support not shown.

Also, pivotally connected to the same support as the bracket 55 by means of the pin 56 is a lever 57, which has an enlarged end 58 extending between the free ends of the thermostatic elements 48 and 51. The other end of the lever 57 is pivotally connected to a rod 60 on which is slidably disposed the contact element 42. The stops 61 and 62 are secured in spaced relation to this rod 63. P0- sitioned between the stops and the contact 42 are compression springs 68 and 64.

Also pivotally secured to the lever 57 on each side of the pivot pin 56 is a pawl. The two pawls are designated by the reference characters 65 and 66. The pawl 66 which is the longest of the pawls engages the teeth on the underside of the ratchet wheel 67 and the shorter pawl 65 engages the teeth on the upperside of the same ratchet wheel 67. The pawls are held in cooperation with the teeth of the ratchet wheel by means of springs 68 and 69 fastened at one end to the corresponding pawl and at the other end to the lever 57. The ratchet wheel 67 is secured to a shaft 7 O, which is adapted to serve as a motor for supplying power for accomplishing work exterior of the electric circuits involved in this device.

The operation of this modification of my invention is substantially the same as the operation of the device shown in Figure 1 and is briefly as follows:

The alternate flexing of the bimetallic elements 48 and 51 results in the pivoting of the lever 57 which, due to the rod 60, moves the contact 42 into alternate engagement with the two contacts 49 and 52, thus alternately breaking one circuit and closing another of the circuits involved in this construction. This modification of the invention clearly indicates that my invention is not limited to use with any particular switch, such, for example, as the mercury switch shown in Figure 1, but may be used with equal advantage with any of the conventional forms of switches.

Now I desire it understood that although I have illustrated and described in detail the preferred elements of my invention, it is not to be thus limited but only in so far as defined by the scope and spirit of the appended claims.

I claim as my invention:

1. In combination with two electric circuits having one common line, a tiltable triterminal mercury switch comprising a tube containing two end terminals and a center terminal connected to said common line, and a globule of mercury of sufficient size to connect either of said end terminals with the center terminal, one of said end terminals being connected to a return line including a thermostatic element operative under the influence of a current flow therethrough, the other of said end terminals being connected to a further return line including a second thermostatic element, said return lines converging into a common line after passage through their respective thermostatic elements, a switch in said common return line for completing a circuit through one end terminal and the center terminal of said mercury switch, the thermostatic element in the completed circuit operating to tilt the mercury switch soon after subjection to the current flow thereby breaking said completed circuit and establishing a circuit past the other of said thermostatic elements whereby said last named-thermostatic element may tilt the mercury switch to its first position, and means for utilizing the tilting motion of said mercury switch to perform work exteriorly of the electrical circuits.

2. In combination with two electric circuits having one common line, a tiltable triterminal mercury switch comprising a tube containing two end terminals and a center terminal connected to said common line, and a globule of mercury of sufficient size to connect either of said end terminals with the center terminal, one of said end terminals being connected to a return line including a thermostatic element operative under the influence of a current flow therethrough, the other of said end terminals being connected to a further return line including a second thermostatic element, said return lines converging into a common line after passage through their respective thermostatic elements, a switch in said common return line for completing a circuit through one end terminal and the center terminal of said mercury switch, the thermostatic element in the completed circuit operating to tilt the mercury switch soon after subjection to the current flow thereby breaking said completed circuit and establishing a circuit past the other of said thermostatic elements whereby said last named thermostatic element may tilt the mercury switch to its first position, and means for utilizing the tilting motion of said mercury switch to perform work eXteriorly of the electrical circuits, said last named means comprising a pawl and ratchet mechanism operative by said switch.

3. In combination with two electric circuits having one common line, a tiltable triterminal mercury switch comprising a tube containing two end terminals and a center terminal connected to said common line, and a globule of mercury of sufficient size to connect either of said end terminals with the center terminal, one of said end terminals being connected to a return line including a thermostatic element operative under the influence of a current flow therethrough, the other of said end terminals being connected to a further return line including a second thermostatic element, said return lines converging into a common line after passage through their respective thermostatic elements, a switch in said common return line for completing a circuit through one end terminal and the center terminal of said mercury switch, the thermostatic element in the completed circuit operating to tilt the mercury switch soon after subjection to the current flow thereby breaking said completed Michigan.

WARREN NOBLE. 

